This invention relates to a suspension device for vehicles, and, more particularly, it is concerned with a suspension device for the front wheels in automotive vehicles such as automobiles, etc..
In the automobiles of a type, wherein the engine is mounted on the front part of the chassis in the direction orthogonal to the longitudinal direction of the vehicle chassis (i.e. the vehicle body) to drive the front wheels, it occurs not infrequently that the length of the front drive shafts is made different between the left and the right sides.
When the length of the left and the right shafts differs each other, the angles of inclination .theta..sub.L and .theta..sub.R of the respective left and right drive shafts extending from the output shaft of the differential gear to the respective left and right wheels become also different. On account of this, there occurs a difference in rotatory moments M.sub.L and M.sub.R which are developed in both left and right wheels by the driving torque at the time of speed acceleration, and which tend to cause the wheels to swing inwardly with the king pin means supporting the wheels as the center of the oscillation. The term "king pin means" is used herein to designate the support means defining the king pin axis (i.e., the steering axis) of the front wheel, whether a king pin shaft or an equivalent support structure is used. Since this rotatory moment increases as the angle of inclination of the drive shaft becomes larger, the relationship between the rotatory moments M.sub.L and M.sub.R is such that M.sub.R is larger than M.sub.L (M.sub.R &gt;M.sub. L) with the result that the steering wheel (hence the vehicle itself) is apt to turn to the side of the longer drive shaft (i.e., to the side of the smaller rotatory moment.
In order therefore to solve the problem of deflection in the steering wheel, various attmepts have so far been made as to reducing the angles of inclination of the left and right drive shafts, or minimizing difference in length between the two drive shafts to the extent possible practicably. However, since the automotive vehicles are subjected to restriction in the diameter of the wheels, the road clearance, tread, and so forth from the standpoints of vehicle design as well as the Government's regulations, the angles of inclination and the lengths of the above-mentioned drive shafts are unavoidably limited. Such difficulty in designing the drive shafts becomes more marked as the size of the vehicles becomes smaller.